The most abundant bird in North America, once estimated to number five billion individuals, is now extinct. The Passenger Pigeon, which resembled our modern Mourning Dove, was driven to extinction by senseless slaughter up until the 1860's when their numbers dropped precipitously. In 1831 John James Audubon, the famous painter of birds, described flocks of these birds, estimated at more than 100 miles wide, that blotted out the sun for days. The last individual of this species died alone in her cage at the Cincinnati Zoo on September 1, 1914, and there will be a nationwide effort to commemorate this tragedy during the centennial year 2014. This book discusses the importance of biodiversity on the planet and explores the lessons of the past as we look to the future and face the continued loss of threatened and endangered species of plants and animals around the world.